import numpy as np import pandas as pd from sklearn.cluster import KMeans from statsmodels.stats.outliers_influence import variance_inflation_factor import statsmodels.api as sm from sklearn.model_selection import train_test_split import warnings import matplotlib.pyplot as plt from sklearn.externals import joblib from sklearn.metrics import accuracy_score warnings.filterwarnings("ignore") def woe_more(item, df, df_woe): xitem = np.array(df[item]) y = df.loc[:, 'target'] y = np.array(y) x = [] for k in xitem: x.append([k]) leastentro = 100 tt_bad = sum(y) tt_good = len(y) - sum(y) l = [] for m in range(10): y_pred = KMeans(n_clusters=4, random_state=m).fit_predict(x) a = [[[], []], [[], []], [[], []], [[], []]] # 第一项为所有值,第二项为违约情况 for i in range(len(y_pred)): a[y_pred[i]][0].append(x[i][0]) a[y_pred[i]][1].append(y[i]) a = sorted(a, key=lambda x: sum(x[0]) / len(x[0])) if sum(a[0][1]) / len(a[0][1]) >= sum(a[1][1]) / len(a[1][1]) >= sum(a[2][1]) / len(a[2][1]) >= sum(a[3][1]) \ / len(a[3][1]) or sum(a[0][1]) / len(a[0][1]) <= sum(a[1][1]) / len(a[1][1]) \ <= sum(a[2][1]) / len(a[2][1]) <= sum(a[3][1]) / len(a[3][1]): entro = 0 for j in a: entro = entro + (- (len(j[1]) - sum(j[1])) / len(j[1]) * np.log((len(j[1]) - sum(j[1])) \ / len(j[1])) - sum( j[1]) / len(j[1]) * np.log(sum(j[1])) / len(j[1])) if entro < leastentro: leastentro = entro l = [] for k in a: l.append([min(k[0]), max(k[0]), np.log((sum(k[1]) / (len(k[1]) - sum(k[1]))) / (tt_bad / tt_good)), sum(k[1]) / len(k[1])]) # print (sum(k[1]),len(k[1])) for m in range(10): y_pred = KMeans(n_clusters=5, random_state=m).fit_predict(x) a = [[[], []], [[], []], [[], []], [[], []], [[], []]] # 第一项为所有值,第二项为违约情况 for i in range(len(y_pred)): a[y_pred[i]][0].append(x[i][0]) a[y_pred[i]][1].append(y[i]) a = sorted(a, key=lambda x: sum(x[0]) / len(x[0])) if sum(a[0][1]) / len(a[0][1]) >= sum(a[1][1]) / len(a[1][1]) >= sum(a[2][1]) / len(a[2][1]) >= sum(a[3][1]) \ / len(a[3][1]) >= sum(a[4][1]) / len(a[4][1]) or sum(a[0][1]) / len(a[0][1]) <= sum(a[1][1]) / len( a[1][1]) \ <= sum(a[2][1]) / len(a[2][1]) <= sum(a[3][1]) / len(a[3][1]) <= sum(a[4][1]) / len(a[4][1]): entro = 0 for k in a: entro = entro + (- (len(k[1]) - sum(k[1])) / len(k[1]) * np.log((len(k[1]) - sum(k[1])) \ / len(k[1])) - sum( k[1]) / len(k[1]) * np.log(sum(k[1])) / len(k[1])) if entro < leastentro: leastentro = entro l = [] for k in a: l.append([min(k[0]), max(k[0]), np.log((sum(k[1]) / (len(k[1]) - sum(k[1]))) / (tt_bad / tt_good)), sum(k[1]) / len(k[1])]) # print (sum(k[1]),len(k[1])) if len(l) == 0: return 0 else: dvars[item] = [] scores[item] = [] df_woe[item] = [0.0] * len(y_pred) print('\n', "Variable:", item, ": has ", len(l), "categories") for m in l: print("span=", [m[0], m[1]], ": WOE=", m[2], "; default rate=", m[3]) dvars[item].append([m[0], m[2]]) scores[item].append([[m[0], m[1]], m[2]]) for i in range(len(y_pred)): if m[0] <= x[i] <= m[1]: df_woe[item][i] = float(m[2]) return 1 def woe3(y_pred, item, df, df_woe): total_bad = sum(df['target']) total_good = len(df['target']) - total_bad woe = [] for i in range(3): # 因分成3类,故是3 good, bad = 0, 0 # 每个变量未响应数和未响应数 for j in range(len(y_pred)): if y_pred[j] == i: if df['target'][j] == 0: good = good + 1 else: bad = bad + 1 if bad == 0: bad = 1 if good == 0: good = 1 # 若一个响应/不响应的也没有,就令其有一个,为避免0和inf。大数据下基本不会出现这种情况 woe.append((i, np.log((bad / good) / (total_bad / total_good)))) df_woe[item] = [0.0] * len(y_pred) for i in range(len(y_pred)): for w in woe: if w[0] == y_pred[i]: df_woe[item][i] = float(w[1]) return woe def woe2(x_pred, item, df, df_woe): total_bad = sum(df['target']) total_good = len(df['target']) - total_bad X = np.array(df[item]) y_pred = KMeans(n_clusters=2, random_state=1).fit_predict(x_pred) # 用聚类算法按变量位置分好类。已经不需要原始变量了 woe = [] judge = [] for i in range(2): good, bad = 0, 0 # 每个变量未响应数和响应数 for j in range(len(y_pred)): if y_pred[j] == i: if df['target'][j] == 0: good = good + 1 else: bad = bad + 1 judge.append([i, bad / (bad + good)]) if bad == 0: bad = 1 if good == 0: good = 1 # 若一个响应/不响应的也没有,就令其有一个,为避免0和inf。大数据下基本不会出现这种情况 woe.append((i, np.log((bad / good) / (total_bad / total_good)))) j0, j1 = [], [] for k in range(len(y_pred)): if y_pred[k] == 0: j0.append(X[k]) if y_pred[k] == 1: j1.append(X[k]) jml = [[np.min(j0), np.max(j0)], [np.min(j1), np.max(j1)]] for l in range(2): judge[l].append(jml[l]) judge = sorted(judge, key=lambda x: x[2]) if judge[1][1] - judge[0][1] > 0: # 违约率升序,则woe也升序 woe = sorted(woe, key=lambda x: x[1]) else: woe = sorted(woe, key=lambda x: x[1], reverse=True) dvars[item] = [] scores[item] = [] for i in range(2): # print("span=", judge[i][2], ": WOE=", woe[i][1], "; default rate=", judge[i][1]) dvars[item].append([judge[i][2][0], woe[i][1]]) scores[item].append([judge[i][2], woe[i][1]]) df_woe[item] = [0.0] * len(y_pred) for i in range(len(y_pred)): for w in woe: if w[0] == y_pred[i]: df_woe[item][i] = float(w[1]) def calculate_woe(df): df_woe = pd.DataFrame() # 构建一个用于存放woe的pd for item in list(df)[1:]: # 连续型变量,使用聚类算法分为三类 X = np.array(df[item]) # 原始表格中的一列 x_pred = [] for it in X: x_pred.append([it]) # 为了进行聚类,对这一列进行处理 ######## flag = 0 print(item, len(set(item))) if len(set(X)) > 4: res = woe_more(item, df, df_woe) if res == 1: continue flag = 1 if 2 < len(set(X)) and flag == 0: for num in range(10): y_pred = KMeans(n_clusters=3, random_state=num).fit_predict(x_pred) # 用聚类算法按变量位置分好类。已经不需要原始变量了 judge = [] for i in range(3): # 因分成3类,故是3 对每一列进行操作 good, bad = 0, 0 # 每个变量响应数和未响应数 for j in range(len(y_pred)): # ypred是那个有012的 if y_pred[j] == i: if df['target'][j] == 0: good = good + 1 else: bad = bad + 1 judge.append([i, bad / (bad + good)]) j0, j1, j2 = [], [], [] for k in range(len(y_pred)): if y_pred[k] == 0: j0.append(X[k]) if y_pred[k] == 1: j1.append(X[k]) if y_pred[k] == 2: j2.append(X[k]) jml = [[np.min(j0), np.max(j0)], [np.min(j1), np.max(j1)], [np.min(j2), np.max(j2)]] for l in range(3): judge[l].append(jml[l]) judge = sorted(judge, key=lambda x: x[2]) if (judge[1][1] - judge[0][1]) * (judge[2][1] - judge[1][1]) >= 0: woe = woe3(y_pred, item, df, df_woe) print('\n', "Variable:", item, ": has 3 categories") if judge[1][1] - judge[0][1] > 0: # 违约率升序,则woe也升序 woe = sorted(woe, key=lambda x: x[1]) else: woe = sorted(woe, key=lambda x: x[1], reverse=True) dvars[item] = [] scores[item] = [] for i in range(3): print("span=", judge[i][2], ": WOE=", woe[i][1], "; default rate=", judge[i][1]) dvars[item].append([judge[i][2][0], woe[i][1]]) scores[item].append([judge[i][2], woe[i][1]]) flag = 1 break if flag == 0: print('\n', "Variable:", item, ": has 2 categories") woe2(x_pred, item, df, df_woe) else: print('\n', "Variable:", item, ": must be 2 categories") woe2(x_pred, item, df, df_woe) df_woe['target'] = df['target'] tar = df_woe['target'] df_woe.drop(labels=['target'], axis=1, inplace=True) df_woe.insert(0, 'target', tar) return (df_woe) def calculate_iv(df): # 计算iv值,返回一个包含列名及其对应iv值的list iv = [] tar = df['target'] tt_bad = sum(tar) tt_good = len(tar) - tt_bad for item in list(df)[1:]: x = df[item] st = set(x) for woe in st: s = 0.0 tt = len(df[df[item] == woe]['target']) bad = sum(df[df[item] == woe]['target']) good = tt - bad s = s + float(bad / tt_bad - good / tt_good) * woe # tt_bad=700,tt_good=300,坏:好=7:3 iv.append([item, s]) return sorted(iv, key=lambda x: x[1]) def filt_by_iv(df, method, alpha): # 根据iv值大小筛选可供使用的变量,默认为20个 iv_list = calculate_iv(df) vars_to_use = [] if method == "thres": for item in iv_list: if item[1] > alpha: vars_to_use.append(item[0]) if method == "number": for i in range(alpha): vars_to_use.append(iv_list[-i - 1][0]) vars_to_use.append('target') vars_to_use.reverse() print("the list after iv is: ") print(vars_to_use) return df[vars_to_use] def calculate_pear(x, y, thres=0.8): r = ((np.dot(x - np.mean(x), y - np.mean(y)) / (len(x) - 1)) / np.sqrt((np.cov(x) * np.cov(y)))) # 相关系数 if abs(r) > thres: return 1 return 0 def remove_pear(df, iv_list, thres=0.8): # 两两比较变量的线性相关性,若pearson相关系数大于thres就将排序靠后的变量剔除,默认thres=0.8 var_set = set(list(df)) length = len(var_set) signals = [0] * length ivd = {} for item in iv_list: ivd[item[0]] = item[1] # 若相关性大,就在s这个list中对其做标记 flag_list = list(var_set) for i in range(length): for j in range(i + 1, length): flag = calculate_pear(df.iloc[:, i], df.iloc[:, j], thres) if flag == 1: if flag_list[i] in ivd and flag_list[j] in ivd: if ivd[flag_list[i]] < ivd[flag_list[j]]: signals[i] = 1 else: signals[i] = 1 # st是所需的集合,要从中移除相关性大的变量 for i in range(length): j = length - 1 - i if signals[j] == 1: var_set.remove(flag_list[j]) print("the list after pearson is:", list(var_set)) return list(var_set) # 返回去除完变量后的list def remove_vif(df, list_after_pear, list_len=20, thres=5.0): the_set = set(list_after_pear) while True: the_list = list(the_set) new_score = [] for i in range(1, len(the_list)): new_df = df.drop([the_list[i]], axis=1) new_ar = np.array(new_df) new_score.append([i, variance_inflation_factor(new_ar, 0)]) m = sorted(new_score, key=lambda x: x[1], reverse=True)[0] # [最小的label,最小的数] score = m[1] if list_len == 0: if score < float(thres): break if list_len != 0: if score < float(thres) or len(the_set) < list_len: break the_set.remove(the_list[m[0]]) final_list = list(the_set) df_final = df[final_list] # print (df_final.head()) tar = df_final.pop('target') df_final.insert(0, 'target', tar) print("the list after vif is:", list(df_final)) return df_final def draw_roc(y_pred, y_test, ks=True): tprlist = [] fprlist = [] auc = 0 ks_list, m1, m2, ks_value = [], [], [], 0 for i in range(1, 1001): thres = 1 - i / 1000 yp = [] for item in y_pred: if item > thres: yp.append(1) else: yp.append(0) Nobs = len(y_test) h1 = sum(yp) t1 = sum(y_test) fn = int((sum(abs(y_test - yp)) + t1 - h1) / 2) tp = t1 - fn fp = h1 - tp tn = Nobs - h1 - fn fpr = fp / (fp + tn) tpr = tp / (tp + fn) tprlist.append(tpr) fprlist.append(fpr) ks_list.append(tpr - fpr) for i in range(999): auc = auc + (fprlist[i + 1] - fprlist[i]) * tprlist[i] print("auc=", auc) plt.plot(fprlist, tprlist) plt.show() if ks: for i in range(10): m1.append(tprlist[i * 100]) m2.append(fprlist[i * 100]) ks_value = max(ks_list) print('ks value=', ks_value) x1 = range(10) x_axis = [] for i in x1: x_axis.append(i / 10) plt.plot(x_axis, m1) plt.plot(x_axis, m2) plt.show() y_pred01 = [] for item in y_pred: if item > 0.5: y_pred01.append(1) else: y_pred01.append(0) print("accuracy score=", accuracy_score(y_pred01, y_test)) def logitreg(df, k=0, ks=True): x = df x1, x0 = x[x['target'] == 1], x[x['target'] == 0] y1, y0 = x1['target'], x0['target'] x1_train, x1_test, y1_train, y1_test = train_test_split(x1, y1, random_state=k) x0_train, x0_test, y0_train, y0_test = train_test_split(x0, y0, random_state=k) x_train, x_test, y_train, y_test = pd.concat([x0_train, x1_train]), pd.concat([x0_test, x1_test]), pd.concat( [y0_train, y1_train]), pd.concat([y0_test, y1_test]) x_train, x_test = sm.add_constant(x_train.iloc[:, 1:]), sm.add_constant(x_test.iloc[:, 1:]) var = list(x_train)[1:] # 备选list st = set() st.add("const") while True: pvs = [] for item in var: if item not in st: l = list(st) + [item] xx = x_train[l] logit_mod = sm.Logit(y_train, xx) logitres = logit_mod.fit(disp=False) pvs.append([item, logitres.pvalues[item]]) v = sorted(pvs, key=lambda x: x[1])[0] if v[1] < 0.05: st.add(v[0]) else: break ltest = list(st) xtest = x_train[ltest] test_mod = sm.Logit(y_train, xtest) testres = test_mod.fit() for item in st: if testres.pvalues[item] > 0.05: st.remove(item) print("We have removed item:", item) print("the list to use for logistic regression:", st) luse = list(st) vars_to_del = [] for item in dvars: if item not in luse: vars_to_del.append(item) for item in vars_to_del: dvars.pop(item) xuse = x_train[luse] logit_mod = sm.Logit(y_train, xuse) logit_res = logit_mod.fit() print(logit_res.summary()) print("the roc and ks of train set is:") y_pred = np.array(logit_res.predict(x_test[luse])) draw_roc(y_pred, y_test, ks) print("the roc and ks of test set is:") y_ptrain = np.array(logit_res.predict(x_train[luse])) draw_roc(y_ptrain, y_train, ks) return logit_res, luse def cal_score(res, x, dvars, q=600, p=20): x = x.loc[:, var_list] params = res.params # 回归得到的参数 const = params['const'] c = pd.DataFrame([1]) for item in var_list: if item != 'const': for i in range(1, len(dvars[item])): if float(x[item]) < dvars[item][i][0]: c[item] = dvars[item][i - 1][1] break if float(x[item]) >= dvars[item][-1][0]: c[item] = dvars[item][-1][1] break c = c.rename(columns={0: "const"}) res = float(logitres.predict(c)) # print("the result of prediction is:", float(logitres.predict(c))) score = q - p / np.log(2) * np.log((1 - res) / res) # print("the credit score is:", score) return (res, score) def get_score(scores, p=20): for item in scores: for k in scores[item]: k[1] = k[1] * p / np.log(2) return scores dvars = {} scores = {} df = pd.read_excel("german.xlsx") df_of_woe = calculate_woe(df) # 计算woe df_of_woe.to_excel("german_woe.xlsx") # 将得到的woe储存 df_of_woe = pd.read_excel("german_woe.xlsx") iv_list = calculate_iv(df_of_woe) df_after_iv = filt_by_iv(df_of_woe, 'number', 20) # 根据iv值选取留下的变量 df_after_pear = remove_pear(df_after_iv, iv_list, 0.1) # 根据pearson相关系数去除线性相关性较高的变量 df_after_vif = remove_vif(df_of_woe, df_after_pear, 0, 5) # 根据vif剔除变量,最少剩20个###### logitres, var_list = logitreg(df_after_vif, 0, ks=True) # joblib.dump(logitres, 'logitres.pkl') # logitmodel = joblib.load('logitres.pkl') # dvars:{'Account Balance': [[1, -0.81809870569494136], [2, -0.26512918778930789], [4, 1.1762632228981755]], 'Duration of Credit (month)': [[4, 0.49062291644847106], [18, -0.10423628844554551], [33, -0.76632879785353658]], 'Payment Status of Previous Credit': [[0, -1.2340708354832155], [2, -0.088318616977396236], [3, 0.50972611843257376]], 'Purpose': [[0, 0.077650934230066068], [5, -0.30830135965451672]], 'Credit Amount': [[250, 0.20782931634116719], [3832, -0.33647223662121289], [8858, -1.0624092400041492]], 'Value Savings/Stocks': [[1, -0.27135784446283229], [2, 0.14183019543921782], [4, 0.77780616879129605]], 'Length of current employment': [[1, -0.43113746316229135], [3, -0.032103245384417431], [4, 0.29871666717548989]], 'Instalment per cent': [[1, 0.1904727690246609], [3, 0.064538521137571164], [4, -0.15730028873015464]], 'Sex & Marital Status': [[1, -0.26469255422708216], [3, 0.16164135155641582]], 'Guarantors': [[1, -0.027973852042406294], [3, 0.58778666490211906]], 'Duration in Current address': [[1, -0.017335212001545787], [3, 0.013594092097163191]], 'Most valuable available asset': [[1, 0.46103495926297511], [2, -0.028573372444056114], [3, -0.21829480143299645]], 'Age (years)': [[19, -0.062035390919452635], [41, 0.17435338714477774]], 'Concurrent Credits': [[1, -0.4836298809575007], [2, -0.45953232937844019], [3, 0.12117862465752169]], 'Type of apartment': [[1, -0.40444522020741891], [2, 0.096438848095699109]], 'No of Credits at this Bank': [[1, -0.074877498932750475], [2, 0.1157104960544109], [3, 0.33135713595444244]], 'Occupation': [[1, 0.078471615441495099], [3, 0.022780028331819906], [4, -0.20441251460814672]], 'No of dependents': [[1, -0.0028161099996421362], [2, 0.015408625352845061]], 'Telephone': [[1, -0.064691321198988669], [2, 0.098637588071948196]], 'Foreign Worker': [[1, -0.034867268795640227], [2, 1.262915339959386]]} x = df.iloc[2:3, 1:] # 从原始数据集中选取一个观测 print("x for test:", x) # 打印出来看一眼 x_score = cal_score(logitres, x, dvars, q=600, p=30) # 得到这个x对应的预测值(01之间)以及得分。 # 默认概率为0.5时为600分,p/1-p每翻一倍多30分 print("x_score:", x_score) credit_score = (get_score(scores, 30)) # 得到每个变量在不同区间时对应的分数 print("credit score list:", credit_score) def get_q(df): s0 = [] s1 = [] q = [] for i in range(len(df)): x = df.iloc[i:i + 1, :] y = int(x['target']) x = x.iloc[:, 1:] score1 = cal_score(logitres, x, dvars, q=600, p=30) if y == 1: s1.append(score1) q.append([score1[0], score1[1], 1]) if y == 0: s0.append(score1[1]) q.append([score1[0], score1[1], 0]) return q def get_graph(q): ss = [] sum_bad = 0 for item in q: ss.append(item[1]) sum_bad = sum_bad + item[2] smin = int(min(ss) - 1) smax = int(max(ss) + 1) d = (smax - smin) / 10 sscores, xais, tp, fp, rate = [], [], [], [], [] for i in range(10): sscores.append(int(smin + i * d)) sscores.append(smax) g, b = 0, 0 pdf = pd.DataFrame( columns=["good_count", "bad_count", "total", "default_rate", "total_percent", "inside_good_percent", "inside_bad_percent", "cum_bad", "cum_good", "cum_bad_percent", "cum_good_percent", "ks"]) for i in range(10): lower = sscores[i] upper = sscores[i + 1] good = 0 bad = 0 for item in q: if item[1] < upper and item[1] >= lower: if item[2] == 1: bad = bad + 1 if item[2] == 0: good = good + 1 b = b + bad g = g + good pdf.loc["[" + str(lower) + "," + str(upper) + ")"] = [good, bad, good + bad, bad / (bad + good), (bad + good) / len(q), good / (len(q) - sum_bad), bad / sum_bad , b, g, b / sum_bad, g / (len(q) - sum_bad), b / sum_bad - g / (len(q) - sum_bad)] xais.append("[" + str(lower) + "," + str(upper) + ")") tp.append(b / sum_bad) fp.append(g / (len(q) - sum_bad)) rate.append(bad / (bad + good)) print(xais) plt.plot(tp) plt.plot(fp) plt.xticks(range(10), xais, rotation=45, fontsize=12) plt.show() plt.plot(rate) plt.xticks(range(10), xais, rotation=45, fontsize=12) plt.show() return (pdf) def get_psi(q, df, logitres, dvars, k=600, l=30): # 需要调用cal_score函数,所以要包含cal_score函数中的参数 ,k,logitres,x,dvars,q=600,p=30 x = df.iloc[:, 1:] x = sm.add_constant(x) y = df['target'] x_train, x_test, y_train, y_test = train_test_split(x, y, random_state=0) ss, sscores, train_list, test_list = [], [], [0] * 10, [0] * 10 for item in q: ss.append(item[1]) smin = int(min(ss) - 1) smax = int(max(ss) + 1) d = (smax - smin) / 10 for i in range(10): sscores.append(int(smin + i * d)) sscores.append(smax) for i in range(len(x_train)): score = cal_score(logitres, x.iloc[i:i + 1, 1:], dvars, q=k, p=l)[1] for j in range(10): if score < sscores[j + 1] and score >= sscores[j]: train_list[j] = train_list[j] + 1 for i in range(len(x_test)): score = cal_score(logitres, x.iloc[i:i + 1, 1:], dvars, q=k, p=l)[1] for j in range(10): if score < sscores[j + 1] and score >= sscores[j]: test_list[j] = test_list[j] + 1 tr_list, te_list = [], [] for item in train_list: tr_list.append(item / sum(train_list)) for item in test_list: te_list.append(item / sum(test_list)) ddf = pd.DataFrame(columns=["train_scope", "train_percent", "test_scope", "test_percent", "PSI"]) for i in range(10): if te_list[i] == 0: ddf.loc[i] = ["[" + str(sscores[i]) + "," + str(sscores[i + 1]) + ")", tr_list[i], "[" + str(sscores[i]) + "," + str(sscores[i + 1]) + ")", te_list[i], np.inf] if te_list[i] != 0: ddf.loc[i] = ["[" + str(sscores[i]) + "," + str(sscores[i + 1]) + ")", tr_list[i], "[" + str(sscores[i]) + "," + str(sscores[i + 1]) + ")", te_list[i], 2.3 * (tr_list[i] - te_list[i]) * np.log(tr_list[i] / te_list[i])] return (ddf) q = get_q(df) print(get_graph(q)) print(get_psi(q, df, logitres, dvars))